Device for intensification of images of invisible radiations comprising an array of sensors,an array of amplifiers and a vacuum image pick-up tube with an array of electrical conductors



Feb, m, 19% E. E. SHELDON 3, 5

IATI COMPRISING AN ARRAY OF SENSORS, AN ARRAY OF AMPLIFIERS AND DEVICE FOR INTENSIFICATION OF IMAGES OF INVISIBLE HAD A VACUUM IMAGE PICK-UP TUBE WITH AN ARRAY OF ELECTRICAL CONDUCTORS 3 Sheets-Sheet 1 Filed Nov. 30, 1965 I-TE-l I 25 Feb. 10, 170 s. E. SHELDON 3,

DEVICE FOR INTENSIFICATION 0F IMAGES OF INVISIBLE RADIATIONS COMPRISING AN ARRAY 0F SENSORS, AN ARRAY OF AMPLIFIERS AND A VACUUM IMAGE PICK-UP TUBE WITH AN ARRAY OF ELECTRICAL CONDUCTORS Filed Nov. 30, 1985 a Sheets-Sheet 2 El El U El -2/ K 25.7" :0 jmki 7 22 Feb. 10, 1% E. E. SHELDON 3,495,084

DEVICE FOR INTENSIFICATION OF IMAGES INVISIBLE RADIATIONS COMPRISING AN ARRAY 0F SENSORS, AN ARRAY OF AMPLIFIERS AND A VACUUM IMAGE PICK-UP TUBE WITH AN ARRAY OF ELECTRICAL CONDUCTORS 3 Sheets-Sheet 3 Filed Nov. 30, 1965 gggo 51 7a $5 n B 5 L, 62 24 {I Q66 f 16 3,495,084 Patented Feb. 10, 1970 3,495,084 DEVICE FOR INTENSIFICATION OF IMAGES OF INVISIBLE RADIATIONS COMPRISING AN AR- RAY OF SENSORS, AN ARRAY OF AMPLIFIERS AND A VACUUM IMAGE PICK-UP TUBE WITH AN ARRAY OF ELECTRICAL CONDUCTORS Edward Emanuel Sheldon, 30 E. 40th St., New York, N.Y. 10016 Filed Nov. 30, 1965, Ser. No. 516,543 Int. Cl. G01t 1/20 US. Cl. 25071.5 19 Claims ABSTRACT OF THE DISCLOSURE The invention relates to new devices for intensification and reproduction of weak images of invisible radiations using in combination an array of sensors connected individually to an array of amplifiers. Each amplifiers of said array of amplifiers is connected individually to the image pick-up vacuum tube. The pick-up tube is provided with an an array of electrical conductors mounted in its endwall for accepting plurality of signal currents representing an image from said array of amplifiers simultaneously and introducing said signal currents in the inside of the tube. In one embodiment of the invention the introduced signal currents are converted into a fluorescent image in the same pick-up tube. In another embodiment, the introduced signal currents are converted into video signals for further transmission and utilization.

This invention relates to an improved solid state device for intensifying images and refers more particularly to an improved device for intensifying images formed by the X-rays which term is meant to include other invisible radiations such as gamma rays and the like, infrared rays and ultraviolet rays and also irradiation by beams of atom particles such as neutrons or electrons and acoustic radiations such as supersonic rays.

The main problem in using X-rays or neutrons or radioisotopes for medical diagnosis is the danger of causing damage to the patient by radiation. The danger of overexposure necessitates the use for a very weak X-ray or neutron beam, which means that the X-ray intensity must be very low and we have, therefore, only a small number of X-ray quanta in the invisible image of the human body. If we do not use all of available X-ray quanta, We will not be able to reproduce an image having all the necessary intelligence, no matter how much we will subse quently intensify this image by electronic means. The solution of this problem is to provide an invisible radiation receptor which will utilize all incoming photons of radiation, which means it Will have quantum efiiciency close to unity. The present X-ray receivers of photoemissive type have a very low quantum efficiency, such as of the order of a fraction of 5% and, therefore, suffer from a basic limitation, as explained above.

The objectives of this invention are obtained by a novel invisible radiation sensitive device. This device has X- ray or neutron receiving screen of material, which exhibits property of producing a current of electrical charges (electrons and position holes) in response to X-rays or neutron beam. The invisible X-ray or neutron image produces, in the invisible radiation sensitive screen, a pattern of electrical charges with a high quantum efliciency, such as approaching unity. The electrical charges have the pattern of the X-ray or neutron image. They cannot, however, be used directly for production of a visible image as they are in many cases too weak. My device provides amplification of said weak charges or potentials by means of a novel mosaic image amplifier of solid state type which amplifies all said charges or potentials simultaneously to the level at which they can be used for production of a visible image. In addition my device provides novel means for the read-out of said amplified charges or potentials and which means may be of a vacuum tube type or of a solid state type.

My device will be especially useful in medicine for radio-isotope images which are always very weak as the amount of radioactive material which can be safely given to the patient is very limited. My invention will be also useful in thermography which means a diagnostic procedure using infrared rays emitted by the body. My device will be also useful for medical diagnosis by means of supersonic images.

It should be understood that my invention is not limited to the use in healing sciences but may be also used for industrial testing and in scientfic research.

The invention will be better understood when taken in connection with the accompanying drawings.

In the drawings:

FIGURE 1 represents a diagrammatic view of the X- ray image intensifier device.

FIGURES 1A, 1B and 1C represent modifications of a vacuum tube type read-out device.

FIGURE 1D represents a solid-state type of read-out device.

FIGURE 2, FIG. 2A and FIG. 2B represent a diagrammatic front view of solid-state read-out device.

FIGURE 3 represents a diagrammatic view of a modification of image intensifying device.

FIGURE 3A represents a modification of image intensifying device.

FIGURES 4 and 4A represent a diagrammatic view of infrared image intensifying device.

FIGURE 5 represents a diagrammatic view of supersonic image intensifying device.

FIGURE 6 represents a diagrammatic view of light image intensifying device.

FIGURE 7 represents a diagrammatic view of novel two-terminal mosaic image amplifier.

FIGURE 1 shows the novel Image Intensifier 1 designed for radio-isotope images. The amount of radioactive material which can be given to the patient with safety is only a few hundreds of microcuries of which only a fraction will be localized in the brain. The prior devices for brain images had to scan patients skull point after point which took more than a half an hour in order to obtain an image of a very crude quality. In my device there is no need for this cumbersome and lengthy scanning. The image of the examined organ such as brain is produced by gamma rays emitted from the examined organ by the radio-isotope used for the particular examination. The emitted gamma rays impinge on the screen 24 reactive to ionizing radiations which may be mounted on the Mosaic Image Intensifer device 17 or may be preferably connected to said intensifier 17 by means of the image conductor 5 to be described below. The screen 24 may be preferably of materials which produce condition currents or charges when irradiated by gamma or other ionizing rays. Such materials are CdS, PbO, Sb S diamond or ZnS. Also two dimensional arrays of N-P or N-P-N or P-N-P junctions made of silicon or germanium may be used as sensors for the screen 24; such junctions are reactive to ionizing radiations.

The image reactive screen 24 may be in the form of a continuous layer or in the form of a mosaic of individual crystals or as a layer divided mechanically into a plurality of separate elements which is necesary if said screen is of a semi-conducting material. Materials such as cadmium sulphide may be prepared in a form of a sintered or plastic layer. The image reactive screen 24 may be also constructed by combining a luminescent layer such as of ZnSAg or NaITl With a photo-conductive layer such as of CdS, CdSe, Sb S or Se either in the form of one mixture layer or in the form of two separate layers.

It should be understood that the image intensifier 1 will be also useful for images produced by atom particles such as beta-rays or alpha-rays or neutrons. In such cases the screen 24 will be modified to make it more sensitive to particular radiation use. For example for neutrons we may use boron, gadolinium, cadmium or indium as neutron reactive screens alone or in combination with the above described sensors for ionizing radiations.

The neutron reactive material described above may be mixed with a fluorescent material such as ZnSAg or NaITl in one layer or may be used as a separate layer. This combined layer may be again combined or joined with a layer of one of photoconductive materials described above: Cds, CdSe, Sb S or Se or PhD to form the screen 24.

In another modification the neutron reactive layer may be mixed into one layer or combined with a separate layer of one of the above photo-conductive materials without the use of a fluorescent material.

The screen 24 may be preferably connected to a source 25 of electrical potential one terminal of which is connected to the conducting layer 2 which is transparent to image forming radiation and which is deposited on the screen 24. The gamma ray or neutron image is converted by the screen 24 or its modifications into a pattern of potentials and charges, which means of electron or holes currents, which can flow through the wires 6 of the image conductor 5 into the read-out device such as vacuum tube 40 or into a solid state device 50 or their modifications. The image conductor 5a may form a part of the endwall 39 of the tube 40 or may be the entire end wall of said tube.

The beam of said electrons or holes has the pattern of the original ionizing radiation image such as X-ray or gamma-ray image. The image conductor 5 comprises a plurality of electrically conducting members such as wires 6 which are embedded in an insulating matrix forming a two dimensional array. The diameter of wires may vary from a small fraction of one millimeter to a few millimeters. The insulating matrix 7 may be of a glass or a suitable plastic such as polyesters, fluorcarbons or polyethylenes. The wires 6 may be also coated with an insulating coating before embedding them in the matrix 7. The insulating coating may end before one or both ends of wire 6 or may continue up to their end leaving only the end-points uncovered. The wires 6 coated or uncoated may extend beyond the free surface 8 of the matrix or may be flush with said surface 8 or may be on one or on both sides of the matrix recessed which means that they terminate before reaching the free surface 8 of the matrix. In case the wires do not reach the surface 8 the remaining path to said surface may be filled with the matrix or may form an open channel according to the needs of the application. The thickness of the image conductor 5 may vary from a fraction of one millimeter to any size needed. The matrix 7 and wires 6 may be light transparent or opaque. The image conductor 5 may be of planar shape, may be of convex shape, or of concave shape, or of any other shape according to the application used. The electrons or holes from screen 24 which enter the conductors 6 are conducted by them across the image conductor 5 into the vacuum tube 40. The image conductor 5 may be mounted in contact with image reactive screen 24 or it may be spaced apart from said screen 24. In such case the conductors 6 extend beyond the image conductor 5 to make an ohmic contact with image reactive screen 24.

It was found that in some cases a space charge was formed at the image conductor 5a and it was preferable to provide on the wall 39 adjacent to the image conductor 5 an electrically conducting layer which allows the removal of said space charge.

It was found that the diameter of conducting members 6 does not control the definition of the images and that definition depends primarily on the size of the end-points 6c and 6a.

. It was further found that the spacing of the conducting members 6 does not affect the definition of images as long as the end-points 6c and 6a of conductors 6 retain the same spatial relationship on their output side as it is on their input side. In this way a charge or potential image is formed by said transmitted electrons or holes on the end-points 6a of conductors 6 and may be stored therein a time sufficient for the read-out of said image. The read-out of this stored electron image may be by means of a fast scanning electron beam, which produces secondary electron emission from the end-points 6a of conductors 6. This secondary electron emission is modulated by the stored electron image at the end points 6a of conductors 6. The emitted secondary electrons may be next fed into electron multipliers and, after multiplication, may be converted into electrical signals in the manner well known in the television art. The end-points 6a of conductors 6 in some cases may be coated with a thin layer of secondary electron emitting material such as MgO, KCl, or Be in order to improve the output of secondary electrons.

Another preferred read-out of the stored electron image in the conductors 6 may be accomplished by using a slow scanning electron beam. In this modification of the invention, the scanning beam 41 is decelerated in front of the conductors 6 by a retarding electrode. The decelerated electron beam is modulated by the electrical charge or potential image on the end-points 6a of conduciors 6. The returning modulated electron beam 42 is fed into electron multipliers and after multiplication, is converted into electrical signals such as video signals as it is well-known in the television art.

In another modification the endpoints 6a of electrical conductors 6 may be coated wtih a photoemissive layer 26, such as of CsSb or of a multi-alkali antimony, such as KCs-Sb or KNaCs-Sb. The photoemissive layer 260 may be in the form of a continuous layer or of a mosaic layer.

In some cases is is preferable to mount the photoemissive layer 26c on a very thin perforated or continuous insulating layer interposed between the end-points 6a and said layer 260. The read-out of the electron image present in the conductors 6 may now be accomplished by means of a scanning light beam mounted outside of the tube 40 instead of a scanning electron beam. The scanning light causes emission of photoelectrons from the layer 26c point after point. This photoemission is modulated by the stored electron image in conductors 6. The emitted photoelectrons may be fed into multipliers and converted into electrical signals.

In another modification shown in FIGURE 1A, the emission of photoelectrons from the layer 26c is produced by a broad and not by a scanning source of light 45. The broad emitted photoelectron beam may be stored in the target 30 of the television camera tube. The readout from the target 30 occurs by means of a scanning elec: tron beam which may be of a fast or of a slow type, as it is known in the television art.

In another modification the photoemissive layer 260 may be mounted on its own support such as mesh screen in a close proximity to the end-points 6a of conductors v 6. The photoemission of electrons from layer 26c will be modulated by the charge or potential image on said endpoints 6a in the same .manner as when using deposition URE 1B, electron beam which is transferred by the image conductor 5 and which appears as a charge or potential image on the end-points of conducting members 6 can be read-out by a broad non-scanning electron beam 38 produced by an electron source 37, such as an electron gun, a cold emission emitter of electrons or a photoemissive emitter of electrons. It should be understood that all said modifications of the electron source apply to all embodiments of my invention. The broad electron beam passes through an aperture 36, is decelerated and irradiates the whole endface of the electron conductor 5 simultaneously in contra-distinction to the scanning electron beam. The returning electron beam is modulated by the pattern of charges or potentials on conductors 6. It is projected or focused on the suitable image reproducing screen 35 such as of luminescent or electro-luminescent material which produces a visible image having the pattern of the original invisible image.

In another modification shown in FIGURE 1C, the broad electron beam after being modulated by charge image on conductors 6 is projected or focused by electrostatic or magnetic means on the target 30a of television camera eye. The target 30:: may be of a semi-conducting glass, MgO, A1 0 or of a photoconductive material such as Sb S or PbO or of material exhibiting electron bombardment induced conductivity such as MgO, or KCl. A semiconducting target 30a is shown in FIGURE 1C. The target 30a is supported by a very thin supporting membrane 30b made of aluminum oxide or a plastic which is pervious to electrons of the returning modulated beam 38a. In some cases the support 301) may be imperforated and the broad beam 38 being at this point of high velocity can penetrate through it well. The tube 44 is provided with electrostatic or electromagnetic deflecting means 44a which serve during the read-out period of operation to provide a scanning motion for the reading electron beam from the source 43.

The broad returning electron beam 38a is stored in the target 30a and can be read-out by the scanning electron beam 41 from an electron source 43. The electron beam 41 may be of a slow type or of a fast type and converts the stored image into video signals as it is known in the art.

It should be understood that all embodiments of my invention may use electrostatic or electromagnetic focusing and scanning means and that the endwalls of the read-out tube may have a plane or a curved shape.

It was found however that in many applications the currents produced by the image forming radiation are too weak to modulate the reading electron beam. The solution of this problem was found in a simultaneous amplification of all currents which represent all image points prior to their readout. This was accomplished by the use of the novel mosaic image amplifier 17 which will be called for the abbreviation sake MAI. The MAI comprises an array of amplifiers 17a arranged into a twodimensional pattern. The number of amplifiers 17a depends on resolution needed for the images to be reproduced, as each amplifier 17a serves to amplify individually and separately the electrical current corresponding to one image point only. The number of image points in an image may vary from a few thousand which is sufiicient for Radio-Isotope Images to a few hundreds of thousands image points, and the number of amplifiers 17a must correspond to the number of said image points. The amplifiers 17a may be of a vacuum type or preferably of solid integrated type. Radioisotope images should have at least 1600 image points which requires the use of 1600 amplifiers 17a. It is possible to use vacuum tube amplifiers such as Nuvistors made by Radio Corporation of America. Such device however is very expensive and bulky. It is preferable therefore to use an array of solid state amplifiers 17a. The solid state amplifiers 17a may be of multi-chip construction, of hybrid construction or preferably integrated construction which means a monolithic construction. In my device the amplification of all electrical currents representing all image points is accomplished simultaneously and therefore it is completely different from sequential amplification of signals representing image points which is known in the prior art.

The solid state amplifier 17a of integrated type is shown in FIGURE 2A. The Mosaic Image Amplifier 17 formed by constructing a two-dimensional array of such amplifiers 17a is shown in FIGURE 2B.

The solid state amplifier 17a can intensify the input signals by a factor of 10 with a good signal to noise ratio. This amplification is necessary when dealing with weak images. The read-out devices even of vacuum type require that the image points have at least a few millivolts potential. In many applications the image forming radiation is so weak that image point have only a fraction of I microvolt potential. In other applications the voltage of image point is sufficiently high but the amperage of currents representing image point is of microamperes strength and such currents were found to be insufficient for an operation of solid state read-out device 50 or its modifications. The use of my novel MAI provides simultaneous pre-amplification of all image points and makes it possible to use the read-out devices both of vacuum type and of solid state type. The integrated solid state amplifier 1711 may be prepared on a monolithic sub-strate of an insulating material such as silicon oxide or gallium arsenide of resistive type.

It was found that solid state amplifiers 17a had a better signal to noise ratio when operating with alternating currents than with DC currents. In view thereof the source of image forming radiation should be pulsed intermittently or mechanical chopping means should be provided such as moving filters or perforated discs. It was found that a great portion of intrinsic noise of the amplifiers 17a lies in a very low frequency of spectrum and that the pulsing of the image forming radiation should be at frequency higher than cycles per second. For low frequency image and for steady radiation image the amplifier 17a may comprise input load resistance between 50,000 ohms and 10 megohms and Darlington amplifier input stage which is well known in the transistor art.

A more advanced type of amplifier 17a may be constructed as described in the Report IS 1152 entitled Low Noise Narrow-Band Amplification With Field Effect Transistors prepared for U.S. Atomic Energy Commission and published by the Clearinghouse of Scientific Information in 1965. A balanced differential amplifier may be included to insure temperature stability and dynamic linear output. If my device is protected from ambient temperature by refrigerated enclosure or by thermistors, the differential amplifier may be omitted. The emitter follower provides effective power drive even at a low output impedance level. The transistors for the integrated amplifier 17a may be of junction type and may be made by diffusion into an N-P silicon wafer. The contacts for the emitter, base and collector may be made by diffusion. The intraconnections may be made by deposition of aluminum and alloying aluminum to contacts. Thin film resistors are deposited by the vacuum evaporation through a suitable mask and are fortified by deposition of silicon oxide. The size of integrated amplifier 17a may be as small as 3 millimeters in diameter. Such integrated ampli fiers will satisfy the desirable signal to noise ratio for my device of 20 to 1. Better signal to noise ratio was obtained by using instead of transistors of junction type described above, the field-effect transistors either of MOS type or of insulated gate type FET. It was found that the production of Mosaic Image Amplifier 17 was im proved and less expensive if the transistors were made by evaporation techniques instead of diffusion process or epitaxial growth. CdS or TeSe lend themselves Well for evaporation of field-effect transistors and are characterized by a low noise level.

It should be understood that there are many modifications of solid state amplifiers 17a and their use comes within the scope of this invention. The MAI17 is interposed between the image reactive screen 24 and its modifications and read-out device 40* and its modifications as it is shown in FIGURE 1. The image reactive screen 24 is connected to the image conductor which was described above and which may be used as a self-supporting member, as it is shown in FIGURE 1. The image conductor 5 may be also mounted on the image reactive screen 24 and may be supported by said screen 24 as it is shown in FIGURE 3. In another modification the image conductor 5 is in contact with the image reactive screen 24 but it is self-supporting.

The image conductor 5 is essentially the same as is described above. Its thickness will vary in accordance with the construction of the device. If it is a supporting member it will be thicker than if it depends for the support on the screen 24 or on MAI17. The conductors 6 make a contact with the surface of the screen 24 and may extend beyond the surface 8 of said conductor plate 5 as shown in FIGURE 1 or may be flush with said surface as it is shown in FIGURE 3. The invisible radiation image as was explained above is converted in screen 24 into a pattern of electrical charges or potentials which flow through to the two-dimensional array of conductors 6 in the form of a plurality of discrete electrical currents having the pattern of the original image. The electrical currents are fed by the image conductor 5 into MAI17 for their intensification. The relation between image conductor 5 and MAI17 is shown in FIGURE 1, in which these two members are self-supporting and are spaced apart from each other. The conductors 6 make contact individually with each of amplifiers 17a in MAI17. It was unexepectedly found that the conductors 6 may follow a curved or irregular course on their way to amplifiers 17a without affecting definition of images provided that the spatial relation of all end-points 6b to each other is the same as of all end-points 60. It was also found that the diameter of conductors 6 beyond their end-points had no effect on definition of images and that said definition depends entirely on the size of end-points 6c in case of a continuous type image screen 24.

Furthermore it was found that the amplifier 17a and end-points 6b of conductors 6 do not have to be in a coaxial relation and that conductors 6 may be connected to the leads of their respective amplifiers 17a at any point of said amplifiers without damaging the definition of images. The conductors 6 are micro-soldered to their respective amplifiers 17a in such a manner that the end-points 6b make contact with the input leads 18 of i the amplifiers 17a which feed said received currents into input area of the amplifiers 17a. Usually the input lead 18 feeds into the emitter area of junction type transistors or into the source area of MOS transistors or of field-effect transistors. In some configurations the input leads 18 may be directed to the base area of the junction transistor or to the gate of the field-elfect transistors.

The amplifiers 17a are arranged in a two dimensional array forming MAI17. Each amplifier 17a is provided with its own output lead 6. The output leads 6 are connected to the collector area of junction type transistors or to drain area of MOS of field effect transistors 10. In some configurations the output leads 6 are connected to the base area of junction transistors or to the gate area of field eifect transistors. It was found that the input leads 18 and the output leads 6 of each amplifier 17a may be on different plane and in different axis without aifecting the definition of images. It was also found that the diameter of leads 18 and 6 and the size of amplifiers 17a had no effect on the definition of images. It was also found that spatial arrangements of amplifiers 17a did not have to correspond to spatial arrangement of conductors 6. In this way the amplified currents from each amplifier 17a which represent individual image points are fed into readout device 40 or its modifications. As it was explained above the conductors 6 between MAI17 and its modifications and read-out device can follow any desired course.

The diameter of conductors 6 between MAI17 and the read-out device may be of any size without affecting the definition of images. The definition depends however on the size of end-points 6a in the read-out device. Reduction of the size of end-points 6a below the size of the end-points 6c will not improve definition much, but enlargement of the size of end-points 6a above the size of the end-points 60 will damage the definition. In the whole image intensification chain only the spatial relationship of end-points 6a to each other must be the same as it is between end-points 6c.

The transistors are 3-terminal devices. They must be provided with anelectrical power for their amplifying operation. The problem of providing thousands of transistors used in MAI17 with electrical power supply without short-circuiting amplifiers 17a was solved by the construction shown in FIGURE 3. The amplifiers 17a are mounted in a two dimensional array in the member 22 made of an electrically conducting material. The member 22 is provided with a two dimensional array of slots or nests 21. Each slot 21 houses one amplifier 17a. The amplifiers 17a are mounted preferably in such a manner that their surface extends above the surface of the member 22. As the amplifiers 17a are mounted on their own dielectric base, they are insulated from the member 22 and from each other. Each amplifier 17a is provided with an electric lead 20 which makes contact to the conducting member 22.

The conducting member 22 is connected to the source of electrical power 25 and transmits the electrical power from said source to all leads 20. The lead 20 follows on the surface of the amplifier 17a and provides electrical power to each transistor of the amplifier 17a. The electrical power brought by lead 20 may be fed into the emitter area or into the base area of junction transistors. In field-efiect or MOS transistors the electrical power will be delivered to the source area or to the gate area of the said transistors.

The conductors 6 which pass through the member 22 on way from the image screen 24 or its modification to MAI17 or its modifications are insulated by a dielectric coating along their entire length except of their end-points. The slots 21 may be perforated for the admission of conductors 6. The conductors 6 pass through the openings 21a in said slots and reach the amplifiers 17a and make a contact with input leads 18.

In some cases supporting member 22 may be of dielectric material and in such case it is provided with a conducting mesh screen which is mounted on the surface of member 22 in such a manner that meshes of the screen surround the slots 21. The mesh screen will be connected with the source of electrical power 25 and will deliver said power to amplifiers 17a by means of conducting plugs mounted in the openings 21a and contacting said mesh screen and said input leads 18.

In some applications the conductors 6 must be flexible and long. In such a case the image conductors 5 is made not in the form of the plate but of the bundle of conductors 6 which are made of glass fibers provided with a metallic conductor within them. The bundle is rigidly fused at one or at its both ends so that it may be vacuum tight at its end for the use as an endwall of the vacuum tube readout device. All the conductors 6 between the ends of said bundle or at least a great number of said conductors 6 are free from each other which means are not connected to each other. This construction will provide a good flexibility for the bundle and will overcome fragility of thin metallic conductors used for the image conductors 5 of plate type. It should be understood that this construction applies to all embodiments of invention.

In another embodiment of my invention the electrical power for all amplifiers 17a in MAI17 and its modifications is provided by a modified image conductor b which is shown in FIGURE 3A. The image conductor 5b has two different types of conductors 6. One type of conductors is made of conductors 6 which are insulated along their entire length except their endpoints. Another group of conductors is made of conductors 6'. The conductors 6 have an area free of insulation which serves to make an electrical contact to the member 26. In addition conductors 6 extend beyond the surface the image conductor 5b only on one side thereof. The screen 26 is of conducting material and makes connection with the source of electrical power 25. The screen 26 has openings 26a which serve for the passage of conductors 6 and 6. The conductors 6 being insulated pass through screen 26 without receiving any electrical power. The conductors 6 being non-insulated at this point receive the electrical power. The conductors 6 and 6 reach MAI17. Conductors 6 make contact with input leads 18. The conductors 6' make contact with leads 20 which distribute the electrical power to all transistors in said amplifiers. In this way MAI17 receives electrical power without making thousands of fanout electrical connections as it was necessary in device of the prior art. The slots 21 may be provided with plugs or other extensions to facilitate the connection between the conducting member 22 and leads 20.

In some cases it is preferable to provide a separate additional ground connection for all transistors in amplifiers 17a. This can be accomplished by using the conducting perforated screen 26b which is connected to the ground. In this modification another set of conductors 6" is required which is similar to the conductors 6 but has an area free from insulation at the point of passage through the screen 26b and not at the point of passage through the screen 26. The conductors 6" extend only on one side of image conductor 5b and reach amplifiers 17a to make the contact with the separate ground leads 20a; the leads 20a extend to the area of the transistors in the amplifier 17a which should be grounded.

In some cases suitably biased diodes are provided in the ground circuit of each amplifier 17a to prevent crosstalk between the adjacent amplifiers 17a.

It should be understood that the screen 26b may be connected to the second terminal of the source of electrical power 25 instead of being connected to the ground.

The screen 2612 for ground connections may be also used in the embodiment of invention shown in FIGURE 3 in which the electrical power is delivered by the conducting member 22. This construction may be also made in a reverse form which means the conducting member 22 is now connected to the ground and the screen 26 or 26b or both of them are connected to the source of electrical power 25. In such case the member 22 will make contact with leads 20a and screen 26 or 261) will make contact with leads 20.

It should be understood that the use of electrical power supplying screen 26 or of ground connection screen 2612 applies to all embodiments of invention.

In cases in which the number of image points is very small, the fan-out construction of electrical conductors may be feasible. In such case all leads 18, 19, 20 and 20a or only leads 20 and 20a may continue beyond the amplifiers 17a or may be micro-soldered to the conducting wires which will connect them with various component parts of the device as it may be required.

All amplifiers 17a after the leads 18, 19 and 20 are formed are encapsulated in a dielectric cover which may be of glass or silicon oxide to protect them from decomposition.

In some applications instead of a vacuum type of read-out device 40 and its modifications, it is preferable to use a solid state read-out device 50 which is shown in FIGURE 1D. The device 50 is constructed -with a plurality of diodes or transistors 51. These diodes emit light either by avalanche break-down or by carriers recombination or by laser effect or other mechanisms. They may be of double diffused junction type and may be made of doped silicon or of gallium phosphide or of gallium arsenide. Diodes 51 are arranged in a two-dimensional array on a suitable support 53, such as of silicon oxide or GaAs of a high resistance. The support 53 is provided with perforations 53a for the passage of signal conductors 6A and of ground conductors 6A. All diodes or transistors 51 are deposited on said monolithic support 53 and are spaced apart from each other at a distance compatible with a definition of images required. The voltages necessary for the breakdown light emission are of the order of a few volts. The amplified signals from MAI17 are fed simultaneously into all light emitting diodes 51 by means of conductors 6A from the image conductor 5b. If the voltage of signals fed by conductors 6A is high enough, light will be emitted from each diode 51. This will reproduce all of the original image simultaneously which was the purpose of this invention.

Conductors 6A are insulated along their entire length except their endpoints. The conductors 6A have an area free of insulation which serves to make an electrical contact to the member 54. The screen 54 is of conducting material and makes connection with the source of electrical power 25. The screen 54 has openings 54a which serve for the passage of conductors 6A and 6A. The conductors 6A being insulated pass through screen 54 without receiving any electrical power. The conductors 6A being non-insulated at this point receive the electrical power. The conductors 6A and 6A reach diodes 51. Conductors 6A make contact with junction area between emitter and base area of diodes 51. Conductors 6A may serve to connect said diodes 51 to the ground or to the source of electrical power. The conductors 6A are connected to the base or to collector area of diodes 51. The conductors 6A do not carry image currents but serve to make an electrical connection with a perforated member 54, which is connected to the ground or to suitable source of electrical power.

FIGURE 2 shows the front view of the solid state readout device 50.

In another modification the perforated member 54 is deposited on the supporting-member 53 and is connected to the collector area or base area of all diodes 51 by means of conducting plugs or fingers which extend through the perforations 54a and perforations 53a in the supporting insulating layer 53. The conducting plugs make electrical connections between the conducting member 54 and diodes 51 and provide ground or electrical power connections to all diodes 51. In this construction the conductors 6A may be eliminated completely. If the supporting member 53 is mounted in front of the array 50 instead of being in the back of said array 50, it does not have to be perforated and may be continuous. In such case the supporting member 53 should be light transparent and may be of materials such as silicon oxide or glass.

In the modification in which screen 54 is connected to the source of electrical power or bias instead of being connected to the ground it is preferable to provide an additional ground connection for all diodes 51. This can be accomplished by using in addition the conducting perforated screen 26b which is connected to the ground as it was described above. In this modification second set of conductors is required which is similar to the first set of conductors 6A but has an area free from insulation at the point of passage through the screen 26b and not at the point of passage through the screen 54. These conductors extend only on one side of image conductor 5b and reach diodes 51.

In one configuration of this embodiment of this invention the conductors 6A will be connected to junction between the emitter and the base, the first set of conductors 6A will be connected to the emitter area and the second set of conductors will be connected to the collector area. It should be understood that other configurations may be used in my device also. In this embodiment of invention the electrical currents from MAI17 which represent image points will modulate the light emission from diodes 51 produced by the application of the electrical power from source 25 and delivered by the screen 54.

In cases in which the number of image points is very small, the fan-out construction of electrical conductors may be used. In such case the diodes 51 are provided with separate leads for each diode. The leads may continue beyond the diodes 51 or may be micro-soldered to other conducting wires which will connect them with ground or with a source of electrical power as it may be required.

In this embodiment the read-out device 50 receives a plurality of electrical currents from MA117 through conductors 6A and converts them into an image simultaneously as distinguished from the sequential or scanning reproduction of images used in the present devices.

It should be understood that the screen 26b may be connected to the second terminal of the source of electrical power 25 instead of being connected to the ground.

In some cases additional suitably biased diodes are provided in the ground circuit of each diode 51 to prevent cross-talk between the adjacent diodes 51.

My device may be also used for detection and reproduction of infrared images. My device can respond to infrared rays of all wave-lengths from one micron to a few millimeters, by the use of a suitable image reactive screen 81. The infrared rays emitted by the human body range from 2 microns to 25 microns wave-length, with the peak of intensity being in 10-12 microns range.

My device may be used therefore as an infrared camera for producing images of internal organs or of the whole bodies by their own emitted infrared rays. For short wavelengths such as 2 microns screen 81 may be of PbS or PbSe, TeSe; for -6 microns wave-lengths IInSb is necessary. For longer wave-lengths silicon or germanium doped with suitable activators such as zinc or gold are necessary. I found that thermistors and bolometers give the widest range of spectral sensitivity as they are reactive to wavelengths from one micron to millimeters.

The infrared image is focused by a suitable optical system such as of lenses, mirrors, fiberoptic image conductor or of a combination thereof onto infrared reactive screen 81 as it is shown in FIGURE 4. The screen 81 is supported by the infrared transparent plate 82 such as of quartz, arsenic trisulphide or of silicon or germanium. If support 82 is of dielectric material an infrared transparent electrically conductive layer 83 such as of silicon is evaporated on it first. On the conductive layer '83 next is deposited a transparent insulating layer 84 such as of silicon oxide or of magnesium oxide or of aluminum oxide. The layer 84 is provided with openings 84a which correspond to the location of terminals of infrared sensitive elements 85 such as bolometers, thermistors, P-N silicon or germanium doped with zinc or gold or other activators or P-I-N diodes. The elements 85 are deposited to form a twodimensional array or a mosaic 86 through a suitable mask. As each element 85 produces one image point, the smaller are such element the better is the definition of the images produced by my device. The thermistors are made of semi-conductive materials such as oxides of metals.

The thermistors, as well as P-N junctions or diodes require for the best operation an electrical bias from the source 25 of electrical power such as battery or from a source of a low frequency unidirectional current. The problem of supplying the electrical bias to many thousands of thermistors or other infrared sensitive elements 85 which form the mosaic 86 was solved by providing the conducting layer 83 with plugs or extensions 83a which are mounted in the openings 84a in the insulating layer 84 and reach terminals 85b of all elements 85 and connect them to one terminal of the battery 25.

The deposition of thermistors or other infrared sensitive elements 85 is done through a suitable mask which will provide proper spacing of the terminals of elements 85 in relation to conducting extensions or plugs 83a, and preferably by evaporation.

The conductors 6 described above make contact with junction areas a of thermistors or other infrared sensitive elements 85. The conductors 6 make contact with the second terminal 85c of all elements '85. The conductors 6 are insulated throughout their length except at their endpoints. The conductors 6 are free from insulation in the area which passes through openings 26a in the conducting screen or perforated member 26. The screen 26 is connected to the source of electrical power 25 or to the ground. The screen 26 may be mounted on the image conductor 5 for the support or may be self supporting. The infrared image is converted in the screen 81 into a plurality of electrical currents which flow through conductors 6 into MAI17 and into read-out devices 40 or 50.

Another construction of the infrared sensitive device is shown in FIGURE 4A and is very similar to the embodiment of the invention shown in FIGURE 3A. In this modification of invention the conducting layer 83 and insulating layer 84 are omitted. The infrared sensitive elements 85 are mounted on the support 82. The conductors 6 are connected to the junction areas 85a. The conductors 6 are connected to the terminals 850 of elements 85. The conductors 6 are insulated throughout their length except at their endpoints and they make contact with the amplifiers 17a of MAI17 or its modifications. The conductors 6' are insulated except in the area which passes through openings 26a in the conducting screen 26. The screen 26 is connected to the source of electrical power 25 or to the ground. The screen 26 may be self supporting or may be mounted on the image conductor 5 for the support. In some applications it is necessary to provide the second perforated member 26b which is connected to the ground or to the second terminal of the electrical power source 25 as was explained above.

The second set of conductors 6" such as shown in FIGURE 3A connects the perforated screen 26b with the terminals 85b of infrared sensitive elements 85.

The infrared image is converted in the screen 81 into a plurality of electrical currents which flow through conductors 6 and are fed into MAI17 or if they are strong enough directly into read-out device 40 or 50 or their modifications.

Furthermore it was found that leads 6 do not have to be straight but may follow a tortuous course and in spite of it the image will be reproduced with a good definition. In addition it was found that conductors 6 can be widely separated from each other and images will not loose their definition. Only the size of the junctions 85a and their spacing from each other was found to control the definition of reproduced images.

The electrical currents corresponding to various image points flow through leads 6 to the array or mosaic 17 of amplifiers 17a for intensification. The currents are of a very low voltage or a low amperage and the integrated MAI17 serves to increase the voltage or amperage of said signals. It was unexpectedly found that although each individual amplifier 17a serves to intensify one image point, the size of amplifiers 17a does not affect the definition of images. This finding made it possible to construct the mosaic 17 of great number of amplifiers 17a such as comprising x 100 or 500 x 500 amplifiers according to the number of image points presents in the image. It was further found that the spatial arrangement of amplifiers 17a may be of any geometrical pattern without destroying the image provided however the output leads from amplifiers which are connected to read-out device 40 or 50 have the same spatial relationship at the read-out device as the thermistors or other elements 85 have in the screen 81.

In some cases the voltage of electrical currents representing individual image points is too low to be amplified by most sensitive amplifiers. For example signals of 10- volts will be obscured by the intrinsic noise of amplifiers 170:. In such cases as it is shown in FIGURE 4A it is necessary to interpose between image conductor 5 and the Mosaic Image Amplifier 17 an array 91 of miniature transformers 90 such as made by Sansui Electric Co. Ltd of Tokyo, Japan and which are about 0.5 cm. in size. Each conductor 6 is connected to the primary of its own transformer 90 which is of step-up type and increases the voltage of signals to the level at which they can be amplified by amplifiers 17a.

The output leads from each step-up transformer 90 are connected to individual amplifiers 1711.

By using the array 91 of transformers 90 the voltage of image signals can be stepped up to such level that they can be now fed into MAI17 or its modifications or they may now be fed directly into a read-out device 40 or 50 or their modifications. It was found that the size of transformers 90 does not affect the definition of images. It was also found that the spatial arrangement of transformers 90 may be of any geometrical pattern without destroying the image provided however that the leads from transformers are connected to the read-out device with the same spatial relationship as the infrared reactive elements 85 have in the screen 81. It was furthermore found that the diameter of primary or secondary windings of transformers 90 did not effect the definition of images.

It should be understood that the construction shown in FIGURE 4 and 4A applies also to all other embodiments of invention especially to devices in which the image reactive screen is made of elements which are electrically semiconducting or conducting.

As the infrared image sensitive elements 85 have a low electrical resistance, it was found that it is preferable to use in amplifiers 17a transistors of junction type instead of a field-effect type. On the other hand the field-effect transistors were found to be the best to use with a high resistance image reactive screen such as of CdS or quartz. In such cases also the resistors in amplifiers 1712 have to be adjusted to match the electrical impedance of elements 85 with the impedance of transistors in amplifiers 17a.

It should be understood that if the infrared sensitive image screen 81 is made of thermocouples or bolometers the device may be simplified as these elements do not require electrical power for operation. In such case the infrared image reactive elements 85 are connected by conductors 6 to MAI17 and the conductors 6' and the perforated member 26 and the source of electrical power 25 may be eliminated. It was found that thermo-couples can be used without MAI17.

It should be understood that all devices described herein may be used at room temperatures or at low temperatures by providing a suitable cooling system. It should be understood that MAI17 may be also used with steady radiation images and with D-C currents produced by them.

It should be understood that my devices are suitable for detection and reproduction of supersonic images as it is shown in FIGURE 5. In this application the image reactive screen 24 is modified to comprise elements reactive to supersonic radiation. The novel screen 24b will comprise supersonic radiation sensitive elements such as piezo-electric members 61 or pressure sensitive transistors 62 such as described in Bell Laboratories Record of December 1962. Screen 24b may be in the form of a continuous piezoelectric layer or may be formed as a twodimensional mosaic of separate elements 61 and 62. The elements 61 may be of quartz, CdS, ZnO, titanates especially of Ba or Pb, niobates or crystals of niobium, lithium sulphate or of Rochelle salt. The elements 61 and 62 convert the supersonic image projected onto them by a focusing system preferably of reflective type 63 into an array of electrical currents which represent individual image points. The electrical currents flow through the conductors 6 and the image conductor 5 or its modifications into MAI17 or its modifications for amplification as it is shown in FIGURE 5. It was found that without the use of novel Mosaic Image Amplifier 17 many medical supersonic examinations were impossible as the amount of supersonic energy compatible with patients safety was not sufiicient to produce electrical signals of the strength necessary to activate even the most sensitive read-out devices. The amplified currents are fed into one of the read-out devices of vacuum type or of solid state type and which were described above. The piezo-electric currents are of alternating type but they will be self-rectified by the read-out devices. It is possible to increase the sensitivity of the supersonic detector 60 by using an array 67 of reversely biased diodes 66 which allow the conduction of the electrical currents carrying the image only in the forward direction. The array 67 of diodes 66 may be interposed between MAI17 and the read-out device or between the supersonic image reactive screen 24b and MAI17. Such array of diodes will provide rectification of piezo-electric currents but it will introduce an additional noise into the system.

It should be understood that various modifications in image intensifying devices used for ionizing radiation images or for infrared images or for supersonic images or for light images may be used for each other.

My device may also serve for intensification and transmission of visible light images. In such case the image re active screen 24 or its modifications may be of light sensitive materials such as Sb S Se, PbO or of semiconducte ing CdS. These materials if made to be of a high resistivity can be used in the form of a continuous layer instead of a mosaic of separate elements.

It should be understood that the image reactive screen 24 may be also made of an array 24c of photo-transistors 70 as shown in FIGURE 6. The image currents produced by such screen 240 will flow into MAI or its modifications for further intensification if it is necessary as was explained above. The photo-transistors 70 may be made of doped silicon or of germanium or of GaAs. They may be of unipolar or bipolar type and they may be of junction type or of field effect type. Photo-transistors 70 are mounted on a light transparent support to produce a twodimensional array. The construction of photo-transistors is similar to that of transistors except that the surface area of emitters is not metallized or if metallized the metallic layer should be light transparent. There are many varieties of photo-transistors such as double-diffused planar N-P-N; single-diffused single epitaxial planar N-P-N; single-diifused double expitaxial planar N-P-N; or singlediifused single epitaxial P-N-P and it should be understood that all modifications of photo-transistors come Within the scope of my invention. The output of photo transistors 70 is in the form of electrical currents and the array 240 of such photo-transistors may serve instead of the image reactive screen 24. The currents from phototransistors 70 may be fed for intensification into MAI17 in the same manner as was described above. The i-nsentified currents from MAI will be delivered to read-out devices such as 40 or 50 or their modifications which will reproduce the original image, as was explained above.

It should be understood that photo-transistors are not sensitive to ionizing radiations such as X-rays but they may be combined together with a fluorescent layer which will convert the ionizing radiation into a fluorescent light first to which they are sensitive.

The photo-transistors are 3-terminal devices. They must be provided with an electrical power for their operation. The problem of providing thousands of photo-transistors 70 with electrical power supply Without short-circuiting them was solved by the construction shown in FIGURE 6. The image conductor 5b has three different sets of conductors 6 for each phototransistor. One is made of conductors 6 which are insulated along their entire length except their endpoints. Other 2 groups of conductors are made of conductors 6 and 6". The conductors 6' have an area free of insulation which serves to make an electrical contact to the member 26. In addition conductors 6' and 6" extend beyond the surface, the image conductor b only on one side thereof. The screen 26 and 22b is of conducting material and makes connection with the source of electrical power 25. The screen 26 and 26b has openings 26a which serve for the passage of conductors 6' and 6". The conductors 6 being insulated pass through screen 26 and 2612 without receiving any electrical power.

The conductors 6' and 6" being non-insulated at the point of passage through the screen 26 and 26b respectively receive the electrical power. The conductor 6 and 6" reach phototransistors 70. Conductors 6 make contact with input emitter junctions. The conductors 6" make contact with base or collector junctions. The conductors 6 and 6" distribute the electrical power to all photo-transistors. In this way screen 24c receives electrical power without making thousands of fan-out electrical connections as it was necessary in devices of the prior art. It should be understood that all my devices may be used not only for the medical diagnosis but also for industrial testing or for research work.

The above described devices reproduce therefore intensified image of visible or invisible radiation simultaneously and not sequentially as it is done in the present art. A simplified modification of all previously described devices is shown in FIG. 7. In this embodiment of invention the transistors in the amplifiers 17a are constructed as two terminal devices which have only one input terminal and one output terminal. This construction removes the need for the electrical power supply for each transistor and eliminates all complicated electrical connections which were described above. The conversion of transistors into two-terminal devices was accomplished by application of mechanical pressure against the junction area between the base and the collector in a junction type transistor and between the gate and drain area in M05 or tensified images of visible or invisible radiation simultaneously and uniformly to all transistors 10 by means of a novel pressure bristle 73. The bristle 73 comprises a plurality of fine dielectric styluses or extensions 77 arranged in a two dimensional pattern. The distribution of styluses 77 must correspond to the distribution of transistors 10 and therefore the bristle 73 is made as a photographic replica of the pattern of the transistors in MAI17. The pressure member 73 may be constructed like the image conductor 5 and the pressure delivering styluses 77 may be formed like conductors 6 but with a greater mechanical strength. The styluses 77 must be entirely dielectric, therefore they are different from the conductors 6 in this respect that they are insulated not only throughout their length but also at their endpoints. In another construction the pressure bristle 73 may be made of a dielectric supporting member to which a bristle of insulated fingers or extensions 77 is attached by soldering or any other processes. The bristle 73 is connected to the sides of the supporting member 22 of MAI17 by movable extensions 74. The motion knobs 75 regulate the tension produced by the bristle 73 against transistors 10. The pressure of a few pounds is necessary to convert standard transistors into a two terminal device. The conductors 6 deliver the image current to the amplifiers 17a through the bristle 73, as was described above. The amplified image currents are transmitted by the next set of conductors 6 to one of the read-out devices as was described above. In conclusion my devices allow simultaneous preamplification of weak images in their entirety and of their corresponding electrical currents which is essential for operation of all read-out devices. This was achieved among other by the use of common means for connecting in a simple and practical construction thousands of input or output or gating areas of transistors to the source of electrical power or to the ground. The term common means indicates that such connecting means such as of a perforated conducting screen 26 or 26/) or screen 22 for all said areas of one terminal type.

Furthermore in my system the simultaneous reproduction of intensified images is accomplished completely or partially by solid state devices which means without the use of any vacuum tubes.

It should be understood that the supersonic image device described above can be used also as a rnicroscopej The supersonic image reactive screen 24b may be made very thin to produce short supersonic waves necessary for microscopic images. In particular the use of evaporated piezoelectric layer such as CdS or ZnO is practical in my device. The use of piezoelectric layers or the use of pressure sensitive transistors 62 will solve the problem of non-uniformity of piezoelectric surfaces of quartz or other crystals.

In another modification supersonic optical system may produce an enlarged supersonic image on the screen 24b reducing thereby the need for a very thin image reactive screen 24b.

It should be understood that in all modifications of invention bipolar transistors or phototransistors may be also used. In addition amplifiers 17a may be constructed vertically instead of being horizontally constructed.

All the particular embodiments and forms of this invention have been illustrated and it is understood that modifications may be made by those skilled in the art, without departing from the full scope and spirit of the foregoing disclosure.

What I claim is:

1. A device for image intensification comprising in combination a plurality of sensor members for receiving an image of an examined area and converting said image into a plurality of individual discrete electrical signal currents, said plurality of currents forming a pattern corresponding to said image, an array of individual amplifying members for said signal currents, said amplifying members producing a plurality of amplified electrical signal currents, means for receiving said amplified electrical currents, said means for receiving said amplified currents comprising a vacuum tube provided on the input side with an end-wall having a plurality of electrically conducting members for transmitting said amplified currents into said tube and storing said currents on said conducting members, said tube comprising furthermore means for producing an electron beam of a slow velocity for irradiating said electrically conducting members, and means for receiving said electron beam returning after said irradiating said conducting members and utilizing said returned beam.

2. A device as defined in claim 1, in which said vacuum tube comprises means for converting said returned electron beam into a fluorescent image.

3. A device as defined in claim 1, in which said device comprises means producing electrical signals corresponding to said stored currents and means for utilizing said electrical signals, in said device furthermore said sensor members spaced apart from said vacuum tube.

4. A device as defined in claim 1, in which said amplifying members comprise means for producing an electrical potential and means for distributing said electrical potential to said ampliyfing members, said distributing means comprsing an electrically conducting apertured member connected to substantially all said amplifying members.

5. A device as defined in claim 1, in which said sensor members comprise X-ray sensitive means of solid-state type, said X-ray sensitive means connected to a source of biasing electrical potential and converting X-rays into electrical currents.

6. A device as defined in claim 1, in which said sensor members comprise X-ray sensitive means of solid-state type and of an electrically semi-conducting material, said semi-conducting material connected to a source of biasing electrical potential.

7. A device as defined in claim 1, in which said sensor members comprise X-ray sensitive means which include X-ray sensitive junctions converting X-rays into electrical currents.

8. A device as defined in claim 1, in which said sensor members comprise X-ray sensitive means of solid-state type converting X-rays into electrical currents and which are free from a luminescent material and comprise photoelectric material.

9. A device as defined in claim 3, in which said sensor members comprise X-ray sensitive means which include photoelectric means converting X-rays into electrical currents.

10. A device as defined in claim 1, in which said amplifying members are of solid-state type and are provided with signal input and signal output areas for receiving said signal currents, said signal input areas and said signal output areas mounted on the same side of said amplifying members.

11. A device as defined in claim 1, in which said amplifying members are provided with a source electrode, a gate electrode and a drain electrode, and in which said source electrode receives said signal currents.

12. A device as defined in claim 1, in which substantially each of said amplifying members is provided with a source electrode, a gate electrode and a drain electrode, and in which said gate electrode receives said signal currents.

13. A device as defined in claim 1, in which said sensor members comprise a compound of niobium.

14. A device as defined in claim 1 which comprises in addition an array of step-up transformers for receiving said amplified signal currents and increasing their voltage.

15. A device as defined in claim 1, in which substantially all of said electrically conducting members in electrical currents in response to sonic radiation.

19. A device as defined in claim 2, in which said sensor members comprises piezo-electric means.

References Cited UNITED STATES PATENTS 1,072,152 9/1913 Ocampo.

1 1,907,124 5/1933 Ruben.

2,069,851 2/ 1937 Rosenberg. 2,909,668 10/1959 Thurlby et a1. 250-213 2,699,511 1/1955 Sheldon 25071 X 2,747,131 5/1956 Sheldon 31511 2,776,377 1/1957 Anger. 3,210,597 10/1965 Siegmund et a1. 3,344,276 9/ 1967 Balding 25071 X RALPH G. NILSON, Primary Examiner M. J. FROME, Assistant Examiner US. Cl. X.R. 

